Hybrid computer system including an analog calculator for rapidly generating electric power system loadflow solutions

ABSTRACT

A hybrid loadflow computer arrangement includes a modularized analog network simulator and a digital computer which acquires and processes on-line data and operator data related to the power system for which a loadflow problem is being solved. The analog simulator includes modular circuits representative of power system buses, lines, generators and loads and the interface between the digital computer and the analog network simulator is provided by analog-to-digital and digital-to-analog converters. The hybrid arrangement operates without iteration, with the analog network simulator providing a bus voltage solution for a set of network simultaneous equations and the digital computer providing generator real power and voltage magnitude set points and real and reactive load power set points. The modular bus circuits are interconnected with the modular generator, load and line circuits to simulate the power system and operate to enforce current and voltage laws to provide the bus solution.

United States Patent Haley et al.

1 1 Jan. 28, 1975 I HYBRID COMPUTER SYSTEM INCLUDING AN ANALOG CALCULATOR FOR RAPlDLY GENERATING ELECTRIC POWER SYSTEM LOADFLOW SOLUTIONS [76] Inventors: Paul H. Haley. Pittsburgh, Pa.;

Mark K. Enns, Ann Arbor. Mich.

[22] Filed: May 19, 1972 [21] Appl. No.: 255,049

[52] U.S. Cl 444/1, 235/l5l.21

[51] Int. Cl...... G06j 1/00. G06f 15/06. G06f 15/56 [58] Field of Search 235/l51.2l, 150.5; 307/18.

[56] References Cited- UNITED STATES PATENTS 3.341.697 9/1967 Kaufman ct al. 235/1505 X 3.582.628 6/1971 Brussolo 235/1505 3.675.002 7/1972 Mitsui et al 235/184 X 3.699.538 10/1972 Van Essen 340/1725 X 3.701.891 10/1972 Cohn 235/184 X OTHER PUBLICATIONS Load Flows by Hybrid Computation for Power System Operations: M. Enns, T. C. Giras, & N. R. Carlson; IEEE Transactions on Power Apparatus and Systems, Nov/Dec. 1971, pp. 2540-2547.

Techniques for the Real-Time Monitoring of Power System Operations; G. W. Stagg, J. F. Dopazo, O. A. Klitin, & L. S. Vanslyck; IEEE Transactions on Power Apparatus and Systems; Vol. PAS-89. No. 4, April 1970, pp. 545-555.

Load Flows Using a Combination of Point Jacobi and Newtons Methods; Y. P. Dusonchet. S. N. Talukdar. H. E. Sinnot; IEEE Transactions on Power Apparatus and Systems; Vol. PAS-90, No. 3, May/June 1971. pp. 941-949.

Computer Control of Power Systems; The Engineer. Oct. 2. I964.

Primary E.ruminerMaIcoIm A. Morrison Assixmn! Emminer-Edward J. Wise Attorney. Agcnl. or FirmF. H. Henson [57] ABSTRACT A hybrid loadflow computer arrangement includes a modularized analog network simulator and a digital computer which acquires and processes on-line data and operator data related to the power system for which a loadt'low problem is being solved. The analog simulator includes modular circuits representative of power system buses, lines, generators and loads and the interface between the digital computer and the analog network simulator is provided by anaIog-to-digital and digital-to-analog converters. The hybrid arrangement operates without iteration, with the analog network simulator providing a bus voltage solution for a set of network simultaneous equations and the digital computer providing generator real power and voltage magnitude set points and real and reactive load power set points. The modular bus circuits are interconnected with the modular generator, load and line circuits to simulate the power system and operate to enforce current and voltage laws to provide the bus solution.

8 Claims, 41 Drawing Figures INJECTION CURRENT VALVES TRANSMIS ION L1NE OUTAGE SWITCHING NETWOZK DIGITAL SIMULATOR V V v LOAD,TIES, Bus VOLTAGE VALVES LINES,8USES GENERATION TRANSFORMERS PATENTEDJANZBIBYS 3.863 .270

- SHEET [11 [1F 23 NORTH l3 EHvIsooKv an) -4 5 G 25 L LOAD 3 34 PHILADELPHIA (2O L2| l2 56 2 3 47v EHV p I4 /38 7 BUFFALO 26 LOAD EHV WASHINGTON r Z22 \MAJsMN /96 23 WHEELING i wEsT LOAD F|G.|

INJECTION CURRENT VALVES A I 4I- D/A /40 TRANSMISSION LINE OUTAGE SWITCHING NETWORK SIMULATOR V V v LOADJIESI BUS VOLTAGE VALVES LINESBUSES GENERATION I TRANSFORMERS PATENTED 3,863,270 SHEET 02 0F 23 BUS 308 I 13K) 1 P 2 e INTEGRATOR a, E p

[ I320 ADMITTANCE i I pq -(E -E TE E406 LINE I S I m mm [323 52 2 3"? I ADMITTANCE I Ypr -(E -E,) v sos (ZINE (p-n) E I I l [325 r324 FIGS ADMITTANCE Y n I N p 1E" }/306 LLINE I -nI LINE OUTAGE SWITCHING I ANALOG A00 4m DIGITAL D/ GENERATION 'fi COMPUTER POWER Q'X AND LINE VOLTAGE MODULES [E] MODULES 1 sET POINTS I BUS VOLTAGES AND LINE CURRENT soLuTIoN F|G.4

p 60 P r I; I L PI 8 E r I, p I @i' {67 TO BUS-P PATENIEB JAN28 ms 3, 863 .270

sum as ur 2 PATENTED 3.863.270

SHEEI GQUF 23 To BUS 7 LINE 1 FROM 22 R BUS J BUSES (TRANSFORMER) 5,7 9 V 6 k LINE T 96 FROM 1/0 TO BUS 9 LOAO 26 FROM I/O &

GENERATOR ANALOG FAULTING MODULES CIRCUITRY PANEL(MANUAL) Dlgfi TAL CONTROL FIG. IOA

PATENIED 3.863.270

SHEET OS [If 23 7 LI AGE SWITCHING A/D BUS VOLTAGE AND LINE CURRENT SOLUTIONS 4'0 I 4l3 4|2- 4II I D/A ANA [E] ANALOG [E] DIGITAL POWER DYNAMIC BUS ANALoG COMPUTER VOLTAGE GENERATOR LINE LOADS I SET POINTS MODULES [1G] MODULES [IT] SWING ANGLEs [E] RoTATIoNAL vELoITIEs ,4I4

D/A INFINITE BUS voLTAGE E TQG AIQS SET POINTS INFINITE BUSES DCU'S FORLOAD ADMITTANGE ADJUSTMENTS FIG. IO

LINE CURRENT AND L BUS voLTAGE soLuTIoNs 1 [4 D/A [I 6] BUS DIGITAL NA oG COMPUTER LINE OUTAGE sE ALOALDS SWITCHING 0 [1L] ANALOG L TIEsAND INFINITE BUSES FIG II DCU'S LoAD ADMITTANcE ADJUSTMENT FAULTING FAULTING DEVICE PATENTED 1 SHEET CBUF 23 FIG. I3A

@WNHQ. 1 J Q. In 4 l Q m a l PATENTED W28 I975 SHEET 07H! 23 FAUL G IBAEUVL G S FAULTING DEVICE PAUL G DEV E C j 451 35! klr D EV 1 3 6] FIG. I6.

PAIENTEU 3. 863 .27 O

SHEET user 23 REAL BUS FIG.|5A.

VOLT INPUT IMAG I NARY BUS VOLT INPUT ALS PAIENIED 3,863,270 sum 10 or 23 ALI FIG. ITA

i An- ALB PATENTEDJANZSIBYS $863,270

SHEET 12 [1F 23 INTRONICS MULTIPLIER INTRONICS MULTIPLIER PATENIED BT SHEET 18 0F 23 O/A INF. BUS vOLTAGES O/A IEI,PM 'GENERATOR SET POINTS MODELS G DATA LINE "TRANsFoIa n-i [IT] "2500 SWITCHING NET THE LINE 983 LINK 4A/D ANALOG SIMULATOR MODELS SOLUTION [E] 982 LOAD AOMITT. LOAD SETTINGS MODELS SYSTEM STuOY OPERATORS MODE FIG.24 

1. A hybrid loadflow computer arrangement comprising a D.C. analog simulator of an AC network, said simulator including a plurality of DC circuits interconnected to correspond to the AC network, a digital computer, said digital computer including means for determining data representative of predetermined network variables, means for generating output signals representative of said data To said plurality of D.C. circuits, and said computer and said simulator including means for generating a loadflow solution with use of said data.
 2. A hybrid loadflow computer arrangement as set forth in claim 1 wherein said plurality of D.C. circuits includes a plurality of bus, generator, load and line D.C. circuits interconnected to correspond to said AC network.
 3. A hybrid loadflow computer arrangement as set forth in claim 2 wherein said signals generated by said digital computer includes generator power and voltage magnitude constraint signals to said generator D.C. circuits, and load power constraint signals to said load D.C. circuits.
 4. A hybrid loadflow computer arrangement as set forth in claim 3 wherein each of said bus D.C. circuits includes means for responding to generator, load and line phasor input current signals and for generating an output bus voltage phasor signal, each of said generator DC. circuits includes means for responding to the difference between actual and constrained generator power signals and for responding to actual and constrained voltage magnitude signals and for generating and output generator current signal, each of said load DC circuits includes means for responding to the difference between actual and constrained load power signals and for generating an output load current phasor signal, and each of said line D.C. circuits includes means for responding to the difference between applied bus voltage phasor signals and generating an output line phasor current signal in accordance with at least a representation of the equivalent series branch impedance.
 5. A hybrid loadflow computer arrangement comprising a D.C. analog simulator of an AC network, said simulator including a plurality of bus D.C. circuits, generator D.C. circuits, load D.C. circuits and line D.C. circuits interconnected to correspond to the AC network, a digital computer, said digital computer including means for providing generator power and voltage magnitude constraints and load power constraints, an analog output system, said computer including means for operating said output system to generate analog constraint signals representive of the digital computer provided generator and load constraints, means for applying the analog constraint signals to corresponding generator and load D.C. circuits, each of said bus D.C. circuits including means for responding to generator, load and line phasor input current signals and for generating an output bus voltage phasor signal, each of said generator D.C. circuits including means for responding to the difference between actual and constrained generator ower signals and for responding to actual and constrained voltage magnitude signals and for generating an output generator current signal, each of said load D.C. circuits including means for responding to the difference between actual and constrained load power signals and for generating an output load current phasor signal, each of said line D.C. circuits including means for responding to the difference between applied bus voltage phasor signals and generating an output line phasor signal in accordance with at least a representation of the equivalent series branch impedance.
 6. A hybrid loadflow computer arrangement as set forth in claim 5 wherein said means for applying said analog constraint signals includes digital-to-analog converter circuitry.
 7. A hybrid loadflow computer arrangement as set forth in claim 5 wherein said means for responding to generator load and line phasor input current signals, said means for responding to the difference between actual and constrained generator signals, said means for responding to the difference between actual and constrained load power signals, and said means for responding to the difference between applied bus voltage phasor signals comprise amplifiers.
 8. A hybrid loadflow computer arrangement as set forth in claim 1 wherein said D.C. circuits comprise moduLar D.C. circuits. 